1. Field of the Invention
This invention relates to arrowheads and more particularly to mechanical broadhead arrow tips with deployable blades.
2. Description of the Related Art
The archery industry has developed variations for folding the blades of a broadhead to serve bow hunters in the field. In these mechanical or expanding-blade broadheads the blades are operably coupled in a manner to allow the blades to move from an in-flight, retracted position to an on-impact, deployed position. The expandable broadhead is beneficial in that it is more aerodynamic than fixed-blade broadheads where the blades may serve as unintended wings and alter the intended flight of the arrow which is traveling at more than 350 feet per second. At that speed, any outside force or imperfection in the broadhead. The goal of a mechanical broadhead with expandable blades is to mimic flight characteristics similar to those of a field point tip while allowing for maximum cutting diameter and lethality more akin to fixed blade broadheads.
The first mechanical broadheads in the industry provided one or more blades partially folded such that the cutting edge was on the radially inward edge of the blade and the entire blade opened by pivoting around a point near the rear of the broadhead body. These blades require rotation from a retracted position to a deployed position about a rearward pivot point upon impact within a target, thereby exposing the cutting edge formed on the blade. Using this type of mechanical broadhead results in a substantial loss in kinetic energy to the blade rotating in a direction opposite to the flight path to end in a deployed position. As a result, less kinetic energy is available for target penetration on impact. In the field, this negative energy transfer leaves the broadhead less lethal resulting in hunting impacts which may only injure the animal. An injured animal may wonder out of an archer's sight. The archer will need to spend a great deal of time searching for the animal, but in many cases he will be unsuccessful which will leave the animal to die a protracted death as a result of its injuries and will ultimately result in a waste of the game animal.
With increasing frequency mechanical broadheads include one or more blades which longitudinally slide relative to the body from the in-flight, retracted position to the on-impact deployed position. During flight, the blades are closely positioned to the body, and upon impact the blades slide rearwardly through a range of motion to the deployed position. Specifically, the blades in this sliding-type mechanical broadhead extend from a longitudinal groove formed in the body such that the cutting edge of the blades extend radially outward from a partially-exposed to fully-exposed diameter. The current designs of such broadheads are less robust or reliable compared with other types of mechanical broadheads. Pins, elastics, gages, rubberbands, or other retaining mechanisms operably couple the blade to the body of the broadhead adding complexity to the design and opportunities for parts to be damaged during use, storage, or shipment. The mechanisms used to retain the broadhead blades during nocking and flight add a layer of unreliability to the broadhead causing them to malfunction at inopportune times such as in-flight or upon impact. Even though a few prior art references have paid passing, cursory mention to the idea of employing magnets in various elements of a mechanical broadhead body, no invention has disclosed how to implement the magnet, a successful implementation has not been disclosed. A need exists to successfully employ a magnet as the sole retaining device for the blade of an expandable broadhead. Despite recent developments in the broadhead art, and in particular use of powder injection molding for the manufacture of components adding significant flexibility in the design and manufacture of blade designs, broadheads still need improvement